Tax-Loss Harvest Executor

WHAT IT DOES

Tax-Loss Harvest Executor helps you identify tokens in your wallet that have lost value since you acquired them, and execute swaps to realize those losses for potential tax benefits. By selling underperforming assets at a loss, you can offset capital gains and reduce your tax liability. The tool reads your wallet's token balances, allows you to input cost basis per token, fetches current market prices, calculates profit/loss per position, and executes swaps via a DEX router of your choice.

HOW TO USE

Connect your wallet using the Connect button. Enter the token address you want to analyze, your cost basis per token in USD, and the amount to sell (0 to sell the entire balance). Click Add Position to add it to your harvest list. The tool will fetch the token symbol, decimals, your balance, and current market price. It will then calculate your total cost, current value, and profit/loss. If the position shows a loss, the Harvest button becomes active. Review the total loss across all positions, then click Execute Harvest to swap each losing position to a stablecoin or native currency.

TECHNICAL MECHANISM

The tool uses ethers.js to interact with ERC20 tokens, reading balances and decimals via balanceOf and decimals methods. It fetches current token prices using a mock price mechanism for demo purposes (in production, it would integrate with a DEX or oracle). The cost basis is provided by the user, which allows the tool to calculate total cost (balance × cost basis) and current value (balance × current price). Profit/loss is the difference between current value and total cost. When executing a harvest, the tool sequentially processes each position, approving the DEX router and calling swapExactTokensForTokens (or swapExactTokensForETH) to convert the token to a stablecoin or native currency. Progress is shown for each position.

WHAT IT CANNOT SEE

This tool cannot guarantee tax compliance in all jurisdictions—tax laws vary and you should consult a tax professional. It cannot accurately determine your cost basis without complete transaction history; you must provide this manually. It cannot predict future tax implications. It cannot verify token legitimacy; you are responsible for ensuring the token address is correct. It cannot recover funds if swaps fail—failed transactions may leave tokens in your wallet. It cannot guarantee that a loss is tax-deductible in your jurisdiction.

PLEASE NOTE

This tool is for EVM-compatible chains only (Ethereum, BNB Chain, Polygon, Avalanche, Arbitrum, Optimism, Base, Fantom, zkSync Era, Linea, Cronos). Always consult a tax professional before harvesting losses. The tool is provided as-is with no warranties. Swaps are executed through a DEX router contract—you must provide the router address.